策略模式干掉if-else，switch

1.传统if -else 写法

String nodeModelStr = "";
if (nodeType == NodeType.START){
  StartModel startModel = JSON.parseObject(nodeModelStr,StartModel.class)
}else if(nodeType == NodeType.END){
  EndModel endModel = JSON.parseObject(nodeModelStr,EndModel.class)
}

2.策略模式写法

使用了lambda表示里，map里key是NodeType，value是方法对象Function<String,BaseModel>(方法入参是String类型，返回值类型是BaseModel)
如下示例中nodeModelStr就是方法入参，返回值是BaseModel

private static Map<NodeType, Function<String,BaseModel>> checkModelTypeDispatcher = new HashMap<NodeType, Function<String, BaseModel>>(){{
        put(NodeType.START,nodeModelStr -> JSON.parseObject(nodeModelStr,StartModel.class));
        put(NodeType.END,nodeModelStr -> JSON.parseObject(nodeModelStr,EndModel.class));
}};
Function<String,BaseModel> function = checkModelTypeDispatcher.get(nodeType);
BaseModel baseModel = function.apply(JSON.toJSONString(node));

3.策略模式的变种

创建策略集合

/**
     * 策略集合
     */
Map<ResGroupType, Consumer<ProcessContext<NotificationModel>>> strategyRelation = new ImmutableMap.Builder<ResGroupType, Consumer<ProcessContext<NotificationModel>>>()
	.put(ResGroupType.CONFIG_RES_GROUP, rewriteConfigResGroupStrategy)
	.put(ResGroupType.VIRTUAL_RES_GROUP, rewriteVirtualResGroupStrategy)
	.build();

创建带参数的获取策略的方法

@Override
public Consumer<ProcessContext<NotificationModel>> getStrategy(ResGroupType resGroupType) {
	Consumer<ProcessContext<NotificationModel>> consumer = strategyRelation.get(resGroupType);
	return Optional.ofNullable(consumer).orElseThrow(() -> new RuntimeException("获取执行策略异常"));
}

主函数执行

this.getStrategy(notificationModel.resGroupType).accept(context);